You have the same problem when trying to show an early mockup to a paying client, they keep picking at things that aren't going to be that way in the final, so you wind up rarely involving them until you have a really solid draft ready. It's a tradeoff you actively make because you're getting paid to make those micro-decisions for them.

It's unfortunate because I feel FOSS could work wonderfully with design, so much of what makes design great also makes FOSS amazing, but the bridge just isn't there.